Magnetic read sensors and related methods having a rear hard bias and no AFM layer

ABSTRACT

Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices. A magnetic read head includes a first pinning layer magnetically oriented in a first direction, and a second pinning layer formed above the first pinning layer and magnetically oriented in a second direction that is opposite of the first direction. The magnetic read head includes a rear hard bias disposed outwardly of one or more of the first pinning layer relative or the second pinning layer. The rear hard bias is magnetically oriented to generate a magnetic field in a bias direction. The bias direction points in the same direction as the first direction or the second direction. The magnetic read head does not include an antiferromagnetic (AFM) layer between a lower shield and an upper shield.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 16/918,848, filed Jul. 1, 2020, which is herein incorporated byreference.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

Aspects of the present disclosure generally relate to magnetic recordingheads of magnetic recording devices, such as magnetic read sensors ofmagnetic read heads of hard disk drives (HDD).

Description of the Related Art

The heart of the functioning and capability of a computer is the storingand writing of data to a data storage device, such as a hard disk drive(HDD). The volume of data processed by a computer is increasing rapidly.There is a need for higher recording density of a magnetic recordingmedium to increase the function and the capability of a computer.

In order to achieve higher recording densities, such as recordingdensities exceeding 2 Tbit/in² for a magnetic recording medium, thewidth and pitch of write tracks are narrowed, and thus the correspondingmagnetically recorded bits encoded in each write track are narrowed.Attempts to achieve increasing requirements of advanced narrow gapreader sensors of read heads to achieve reading of higher recordingdensities have been proposed.

However, attempts to increase recording densities involve complexitiesand costs in forming magnetic sensors, alignment complexities, headinstability, thickness limitations, corrosion concerns, shingledmagnetic recording (SMR) trimming, and resolution penalties.

As an example, including an antiferromagnetic (AFM) layer in magneticsensors can involve specialized stitching processes and separatedeposition of the AFM layer in certain configurations, and can involvecorrosion in certain configurations. Including an AFM layer can alsootherwise involve relatively decreased resolutions due to the finitethickness range of the AFM layer required.

Therefore, there is a need in the art for an improved magnetic readhead.

SUMMARY OF THE DISCLOSURE

Aspects of the present disclosure generally relate to magnetic recordingheads of magnetic recording devices. A magnetic read head includes afirst pinning layer magnetically oriented in a first direction, and asecond pinning layer formed above the first pinning layer andmagnetically oriented in a second direction that is opposite of thefirst direction. The magnetic read head includes a rear hard biasdisposed outwardly of one or more of the first pinning layer relative orthe second pinning layer. The rear hard bias is magnetically oriented togenerate a magnetic field in a bias direction. The bias direction pointsin the same direction as the first direction or the second direction.The magnetic read head does not include an antiferromagnetic (AFM) layerbetween a lower shield and an upper shield.

In one implementation, a magnetic read sensor includes a first pinninglayer magnetically oriented in a first direction. The first pinninglayer includes an inward end at a media facing surface and an outwardend. A second pinning layer is formed above the first pinning layer andmagnetically oriented in a second direction that is opposite of thefirst direction. The second pinning layer includes an inward end at themedia facing surface and an outward end. A spacer layer is between thefirst pinning layer and the second pinning layer. A free layer is formedabove the second pinning layer, and the free layer includes an inwardend disposed at the media facing surface and an outward end. A barrierlayer is between the second pinning layer and the free layer. A rearhard bias is disposed outwardly of the first pinning layer relative tothe media facing surface. The rear hard bias is magnetically oriented togenerate a magnetic field in a bias direction that points in the samedirection as the first direction of the first pinning layer.

In one implementation, a magnetic read sensor includes a first pinninglayer magnetically oriented in a first direction. The first pinninglayer includes an inward end at a media facing surface and an outwardend. A second pinning layer is formed above the first pinning layer andmagnetically oriented to in a second direction that is opposite of thefirst direction. The second pinning layer includes an inward end at themedia facing surface and an outward end. A spacer layer is between thefirst pinning layer and the second pinning layer. A free layer formedabove the second pinning layer, and the free layer includes an inwardend disposed at the media facing surface and an outward end. A barrierlayer is between the second pinning layer and the free layer. A rearhard bias is disposed outwardly of the second pinning layer relative tothe media facing surface, and the rear hard bias is magneticallyoriented to generate a magnetic field in a bias direction. The biasdirection points in the same direction as the second direction of thesecond pinning layer.

In one implementation, a magnetic read sensor includes a lower shield,and a first pinning layer formed above the lower shield and magneticallyoriented in a first direction. The first pinning layer includes aninward end at a media facing surface and an outward end. The magneticread sensor also includes a second pinning layer formed above the firstpinning layer and magnetically oriented in a second direction that isopposite of the first direction. The second pinning layer includes aninward end at the media facing surface and an outward end. The magneticread sensor also includes a free layer formed above the second pinninglayer, and the free layer includes an inward end disposed at the mediafacing surface and an outward end. The magnetic read sensor alsoincludes an upper shield formed above the free layer, and a first sideshield formed on a first side of the first pinning layer, the secondpinning layer, and the free layer. The first side shield includes asingle material layer structure coupled to the upper shield andseparated from the lower shield through an insulation layer. Themagnetic read sensor also includes a second side shield formed on asecond side of the first pinning layer, the second pinning layer, andthe free layer. The second side shield includes a single material layerstructure coupled to the upper shield and separated from the lowershield through an insulation layer.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a schematic illustration of a magnetic recording deviceincluding a magnetic write head and a magnetic read head, according toone implementation.

FIG. 2 is a schematic illustration a cross sectional side view of a headassembly facing the magnetic disk or other magnetic storage medium,according to one implementation.

FIG. 3A is a schematic illustration of a side view of a magnetic readhead, according to one implementation.

FIG. 3B is a schematic illustration of a top view of the magnetic readhead shown in FIG. 3A, according to one implementation.

FIG. 3C is a schematic illustration of a front view of the magnetic readhead shown in FIG. 3A, according to one implementation.

FIG. 4A is a schematic illustration of a side view of a magnetic readhead, according to one implementation.

FIG. 4B is a schematic illustration of a top view of the magnetic readhead shown in FIG. 4A, according to one implementation.

FIG. 4C is a schematic illustration of a front view of the magnetic readhead shown in FIG. 4A, according to one implementation.

FIG. 5A is a schematic graphical illustration of magnetic reader widthsof multiple cases of magnetic recording heads, according to variousimplementations.

FIG. 5B is a schematic graphical illustration of skirt ratios ofmultiple cases of magnetic read heads, according to variousimplementations.

FIG. 5C is a schematic graphical illustration of linear resolutions ofmultiple cases of magnetic read heads, according to variousimplementations.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments of the disclosure.However, it should be understood that the disclosure is not limited tospecific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practice thedisclosure. Furthermore, although embodiments of the disclosure mayachieve advantages over other possible solutions and/or over the priorart, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the disclosure. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s). Likewise, reference to“the disclosure” shall not be construed as a generalization of anyinventive subject matter disclosed herein and shall not be considered tobe an element or limitation of the appended claims except whereexplicitly recited in a claim(s).

Aspects of the present disclosure generally relate to magnetic recordingheads of magnetic recording devices. A magnetic read head includes afirst pinning layer magnetically oriented in a first direction such thata magnetization of the first pinning layer is aligned with the firstdirection. The first direction is perpendicular to a media facingsurface (MFS) and is parallel to a reader stripe height direction. Themagnetic read head also includes a second pinning layer formed above thefirst pinning layer and magnetically oriented in a second direction thatis opposite of the first direction. The second pinning layer ismagnetically oriented in the second direction such that a magnetizationof the second pinning layer is aligned with the second direction. Themagnetic read head includes a rear hard bias disposed outwardly of oneor more of the first pinning layer relative or the second pinning layer.The rear hard bias is magnetically oriented to generate a magnetic fieldin a bias direction. The bias direction points in the same direction asthe first direction or the second direction. The magnetic read head doesnot include an antiferromagnetic (AFM) layer between a lower shield andan upper shield.

It is to be understood that the magnetic recording head discussed hereinis applicable to a data storage device such as a hard disk drive (HDD)as well as a tape drive such as a tape embedded drive (TED) or aninsertable tape media drive. An example TED is described in co-pendingpatent application titled “Tape Embedded Drive,” U.S. application Ser.No. 16/365,034, filed Mar. 31, 2019, assigned to the same assignee ofthis application, which is herein incorporated by reference. As such,any reference in the detailed description to a HDD or tape drive ismerely for exemplification purposes and is not intended to limit thedisclosure unless explicitly claimed. Furthermore, reference to orclaims directed to magnetic recording devices are intended to includeboth HDD and tape drive unless HDD or tape drive devices are explicitlyclaimed.

It is also to be understood that aspects disclosed herein, such as themagnetoresistive devices, may be used in magnetic sensor applicationsoutside of HDD's and tape media drives such as TED's, such as spintronicdevices other than HDD's and tape media drives. As an example, aspectsdisclosed herein may be used in magnetic elements in magnetoresistiverandom-access memory (MRAM) devices (e.g., magnetic tunnel junctions aspart of memory elements), magnetic sensors or other spintronic devices.

FIG. 1 is a schematic illustration of a magnetic recording device 100including a magnetic write head and a magnetic read head, according toone implementation. The magnetic recording device 100 is a magneticmedia drive. The magnetic recording device 100 may be a singledrive/device or may include multiple drives/devices. The magneticrecording device 100 includes a magnetic recording medium, such as oneor more rotatable magnetic disks 112 supported on a spindle 114 androtated by a drive motor 118. For the ease of illustration, a singledisk drive is shown according to one embodiment. The magnetic recordingon each magnetic disk 112 is in the form of any suitable patterns ofdata tracks, such as annular patterns of concentric data tracks on themagnetic disk 112.

At least one slider 113 is positioned near the magnetic disk 112. Eachslider 113 supports a head assembly 121 including one or more magneticrecording heads (for example read/write heads), such as a write head andsuch as a read head including a TMR device. As the magnetic disk 112rotates, the slider 113 moves radially in and out over the disk surface122 so that the head assembly 121 may access different tracks of themagnetic disk 112 where desired data are written or read. Each slider113 is attached to an actuator arm 119 by way of a suspension 115. Thesuspension 115 provides a slight spring force which biases the slider113 toward the disk surface 122. Each actuator arm 119 is attached to anactuator 127. The actuator 127 as shown in FIG. 1 may be a voice coilmotor (VCM). The VCM includes a coil movable within a fixed magneticfield, the direction and speed of the coil movements being controlled bythe motor current signals supplied by control unit 129.

During operation of the magnetic recording device 100, the rotation ofthe magnetic disk 112 generates an air or gas bearing between the slider113 and the disk surface 122 which exerts an upward force or lift on theslider 113. The air or gas bearing thus counter-balances the slightspring force of suspension 115 and supports slider 113 off and slightlyabove the disk surface 122 by a small, substantially constant spacingduring normal operation.

The various components of the magnetic recording device 100 arecontrolled in operation by control signals generated by control unit129, such as access control signals and internal clock signals. Thecontrol unit 129 includes logic control circuits, storage means and amicroprocessor. The control unit 129 generates control signals tocontrol various system operations such as drive motor control signals online 123 and head position and seek control signals on line 128. Thecontrol signals on line 128 provide the desired current profiles tooptimally move and position slider 113 to the desired data track on disk112. Write and read signals are communicated to and from the headassembly 121 by way of recording channel 125. In one embodiment, whichcan be combined with other embodiments, the magnetic media drive of FIG.1 may further include a plurality of media, or disks, a plurality ofactuators, and/or a plurality number of sliders.

FIG. 2 is a schematic illustration a cross sectional side view of a headassembly 200 facing the magnetic disk 112 or other magnetic storagemedium, according to one implementation. The head assembly 200 maycorrespond to the head assembly 121 described in FIG. 1. The headassembly 200 includes a media facing surface (MFS) 212, such as an airbearing surface (ABS), facing the magnetic disk 112. As shown in FIG. 2,the magnetic disk 112 relatively moves in the direction indicated by thearrow 232 and the head assembly 200 relatively moves in the directionindicated by the arrow 233.

The head assembly 200 includes a magnetic read head 211. The magneticread head 211 include a sensing element 204 disposed between shields S1and S2. The sensing element 204 and the shields S1 and S2 have the MFS212 facing the magnetic disk 112. The sensing element 204 is a TMRdevice sensing the magnetic fields of the recorded bits, such asperpendicular recorded bits or longitudinal recorded bits, in themagnetic disk 112 by a TMR effect. In one embodiment, which can becombined with other embodiments, the spacing between shields S1 and S2is 20 nm or less.

The head assembly 200 includes a write head 210. The write head 210includes a main pole 220, a leading shield 206, and a trailing shield(TS) 240. The main pole 220 comprises a magnetic material and serves asa main electrode. Each of the main pole 220, the leading shield 206, andthe trailing shield (TS) 240 has a front portion at the MFS. The writehead 210 includes a coil 218 around the main pole 220 that excites themain pole 220 to produce a writing magnetic field for affecting amagnetic recording medium of the rotatable magnetic disk 112. The coil218 may be a helical structure or one or more sets of pancakestructures. The TS 240 includes a magnetic material, serving as a returnpole for the main pole 220. The leading shield 206 may provideelectromagnetic shielding and is separated from the main pole 220 by aleading gap 254.

FIG. 3A is a schematic illustration of a side view of a magnetic readhead 300, according to one implementation, and may be used as themagnetic read head 211 shown in FIG. 2. The side view shown is a throatview, or an APEX view, of the magnetic read head 300. The magnetic readhead 300 includes a magnetic sensor 301 sandwiched between a lowershield S1 and an upper shield S2. The magnetic sensor 301 includes aseed layer 303 formed on and above the lower shield S1, and a firstpinning layer 305 formed on and above the seed layer 303. A secondpinning layer 307 is formed above the first pinning layer 305, and aspacer layer 309 is formed between the first pinning layer 305 and thesecond pinning layer 307. A free layer 311 is formed above the secondpinning layer 307, and a barrier layer 315 is formed between the freelayer 311 and the second pinning layer 307. A cap layer 313 is formedbetween the free layer 311 and the upper shield S2. The upper shield S2is formed above the free layer 311 and above the cap layer 313.

In FIG. 3A, cross-sectional hatching for the cap layer 313, the barrierlayer 315, and the spacer layer 309 is omitted for ease of visualreference.

The magnetic read head 300 includes a media facing surface (MFS) 312such as an air bearing surface (ABS). Inward ends of each of the seedlayer 303, the first pinning layer 305, the spacer layer 309, the secondpinning layer 307, the barrier layer 315, the free layer 311, and thecap layer 313 are disposed at the MFS 312. As an example, an inward end317 of the first pinning layer 305 is disposed at the MFS 312, and aninward end 319 of the free layer is disposed at the MFS 312. An outwardend 321 of the first pinning layer 305 is disposed outwardly of anoutward end 350 of the second pinning layer 307 relative to the MFS 312.The outward end 321 of the first pinning layer 305 is also disposedoutwardly of an outward end 351 of the free layer 311. The outward end350 of the second pinning layer 307 and the outward end 351 of the freelayer 311 are disposed inwardly of the outward end 321 of the firstpinning layer 305 relative to the MFS 312.

The seed layer 303 is formed of a material that includes one or more ofTa, W (tungsten), Ru, Cr, Co, Ti, and/or Hf. Each of the first pinninglayer 305 and the second pinning layer 307 is magnetic and is formed ofa material that includes one or more of Co, Fe, B, Ni, and/or an alloythereof. In one example, the first pinning layer 305 and/or the secondpinning layer 307 include an alloy, such as CoFe or NiFe. The spacerlayer 309 is nonmagnetic and is formed of a metal material. In oneembodiment, which can be combined with other embodiments, the metalmaterial of the spacer layer 309 is Ru. The spacer layer 309 is of athickness T2. The thickness T2 is within a range of 4 Å to 9 Å. In oneexample, the thickness T2 is within a range of 4 Å to 5 Å or within arange of 8 Å to 9 Å. The spacer layer 309 facilitates the magnetizationsof the first and second pinning layers 305, 307 being anti-parallel toeach other. In one example, the spacer layer 309 facilitates an RKKYinteraction between the first and second pinning layers 305, 307. Thebarrier layer 512 is nonmagnetic and includes MgO, aluminum oxide(AlxOx) such as Al2O3, or any other suitable insulation material. Thecap layer 313 includes one or more of W, Ta, Ru, Cr, Ti, Hf, and/or anyother suitable cap material. The free layer 311 is formed of a materialthat includes one or more of Ni, Fe, Co, B, and/or Hf.

The magnetic read head 300 includes a rear hard bias (RHB) 323 disposedoutwardly of the first pinning layer 305 relative to the MFS 312. In oneembodiment, which can be combined with other embodiments, the RHB 323includes a seed layer 324 (shown in ghost), a magnetic layer 325 formedon the seed layer 324, and a nonmagnetic cap layer 327 (shown in ghost)formed on the magnetic layer 325. The seed layer 324 may be similar toor different from the seed layer 303 between the first pinning layer 305and the lower shield S1, and may include one or more aspects, features,components, and/or properties of the seed layer 303. An upper end 326 ofthe RHB 323 is aligned with (shown in ghost as 326′ in FIG. 3A) or above(as shown in FIG. 3A) an upper end 329 of the first pinning layer 305along the thickness direction. In one example, the upper end 326 of theRHB 323 is exclusive of the nonmagnetic cap layer 327 such that theupper end 326 of the RHB 323 is the upper end of the magnetic layer 325.A lower end 337 of the magnetic layer 325 is aligned with or below alower end 338 of the first pinning layer 305. A lower end of the RHB323, such as the lower end 337 of the magnetic layer 325 or a lower endof the seed layer 324, may be aligned with or below a lower end of theseed layer 303. A lower end of the RHB 323, such as the lower end 337 ofthe magnetic layer 325 or the lower end of the seed layer 324, mayextend into the lower shield S1. The upper end 326 of the RHB 323 isbelow an upper end 331 of the second pinning layer 307 along thethickness direction. The present disclosure contemplates that the upperend 326 of the RHB 323 may be aligned with or above the upper end 331 ofthe second pinning layer 307. The upper end 326 of the RHB 323 may bealigned with or above an upper end of the spacer layer 309. The magneticsensor 301 of the magnetic read head 300 also includes an insulationmaterial 333 formed above the RHB 323, above an outward portion of thefirst pinning layer 305. The insulation material 333 is also formedoutwardly of the spacer layer 309, the second pinning layer 307, thebarrier layer 315, the free layer 311, and the cap layer 313. Themagnetic read head 300 also includes an insulation layer 370 formedbetween the RHB 323 and the first pinning layer 305, between the RHB 323and the second pinning layer 307, between the RHB 323 and the spacerlayer 309, and between the RHB 323 and the seed layer 303. The magneticread head 300 also includes an insulation layer 371 formed between theRHB 323 and the lower shield S1. The RHB 323 is separated from the firstpinning layer 305 using the insulation layer 370. In FIG. 3A,cross-sectional hatching for the insulation layer 370 and the insulationlayer 371 is omitted for ease of visual reference.

The magnetic layer 325 of the RHB 323 is formed of a material having ahigh coercivity, such as a material that includes one or more of Co, Ptand/or Cr, such as CoPt or CoPtCr. The insulation material 333 is formedof a material including MgO, aluminum oxide (AlxOx), silicon oxide(SixOx), silicon nitride (SixNx), or any other suitable insulationmaterial. The RHB 323 is of a thickness T1 that is 50 nm or less, suchas 20 nm.

The layers 303, 305, 307, 309, 311, 313, and 315 are formed on the lowershield S1 using a deposition process such as physical vapor deposition(PVD) sputtering, ion beam deposition (IBD), electroplated deposition,atomic layer deposition (ALD), or chemical vapor deposition (CVD). Thelayers of the magnetic sensor 301 are milled (such as by using ionmilling) or etched to form openings for the RHB 323 and the insulationmaterial 333. The openings are then refilled with the insulation layer370, the insulation layer 371, the RHB 323 and the insulation material333 using one or more deposition processes. In one example, a full millis conducted in the track width direction that extends fully from oneside of the layers to an opposite side of the layers in the track widthdirection; a partial mill is conducted in the thickness direction thatstops at or above the upper end 329 of the first pinning layer 305; anda full mill is conducted in the thickness direction outward of the firstpinning layer 305 that stops at or into the lower shield S1

The magnetizations of the first pinning layer 305 and the second pinninglayer 307 are oriented in an antiparallel orientation with respect toeach other. The first pinning layer 305 is magnetically oriented in afirst direction D1. The first pinning layer 305 is magnetically orientedsuch that a magnetization of the first pinning layer 305 is aligned withthe first direction D1. The first direction D1 points outwardly and awayfrom the MFS 312, is perpendicular to the MFS 312, and is parallel tothe stripe height direction. The second pinning layer 307 ismagnetically oriented in a second direction D2 that is opposite of thefirst direction D1. The second pinning layer 307 is magneticallyoriented such that a magnetization of the second pinning layer 307 isaligned with the second direction D2. The magnetic layer 325 of the RHB323 is oriented to generate a magnetic field in a bias direction D3. Thebias direction D3 points in the same direction as the first direction D1along the stripe height direction. The first direction D1 pointsoutwardly and away from the MFS 312. The second direction D2 pointsinwardly and toward the MFS 312. The bias direction D3 points outwardly,away from the MFS 312, and away from the first pinning layer 305.

The magnetic field in the bias direction D3 applies magnetic force tothe first pinning layer 305 and stabilizes the magnetization of thefirst pinning layer 305. Due to antiparallel coupling between the firstand second pinning layers 305, 307 facilitated using the spacer layer309 that includes the thickness T2, the magnetization in the seconddirection D2 will be oriented 180 degrees relative to the magnetizationof the first pinning layer 305 in the first direction D1. Themagnetizations are also maintained substantially in the first and seconddirections D1, D2. The RHB 323 applies magnetic force to the firstpinning layer 305 that is larger than any magnetic force—if any—appliedto the second pinning layer 307 by the RHB 323. Large shape anisotropy(due to a long height H1 described below) and transverse Hk inducedalong the stripe height direction (due to compressive stress andpositive magnetostrictive properties of the first and second pinninglayers 305, 307) on the first and second pinning layers 305, 307 furtherstabilize the magnetizations of the first and second pinning layers 305,307.

The present disclosure contemplates that the first direction D1, thesecond direction D2, and the bias direction D3 may be reversed such thatthe second direction D2 points outwardly, and the first direction D1 andthe bias direction D3 point inwardly.

The first pinning layer 305 includes a height H1 in the stripe heightdirection. The height H1 is larger than respective heights of the spacerlayer 309, the second pinning layer 307, the barrier layer 315, the freelayer 311, and the cap layer 313. The height H1 is 100 nm or less, suchas within a range of 30 nm to 90 nm. In one example, the height H1 is atleast double a height of the second pinning layer 307. In oneembodiment, which can be combined with other embodiments, the height H1of the first pinning layer 305 may be approximately equal to therespective heights of the spacer layer 309, the second pinning layer307, the barrier layer 315, the free layer 311, and the cap layer 313.In such an embodiment, a height of the RHB 323 in the stripe heightdirection may be larger than in the implementation shown in FIG. 3A, andis about equal to a height of the insulation material 333 in the stripeheight direction. In such an embodiment, the upper end 326 of the RHB323 is aligned with or below the upper end 329 of the first pinninglayer 305. In one example, the upper end 326 of the RHB 323 is exclusiveof the nonmagnetic cap layer 327 such that the upper end 326 of the RHB323 is the upper end of the magnetic layer 325. In such an embodiment, aheight of the seed layer 303 may be lesser than in the implementationshown in FIG. 3A, and is approximately equal to the height H1 of thefirst pinning layer 305 and approximately equal to the respectiveheights of the spacer layer 309, the second pinning layer 307, thebarrier layer 315, the free layer 311, and the cap layer 313. In theimplementation shown in FIG. 3A, the height of the RHB 323 is lesserthan the height of the insulation material 333.

FIG. 3B is a schematic illustration of a top view of the magnetic readhead 300 shown in FIG. 3A, according to one implementation. The uppershield S2 and the cap layer 313 are omitted in FIG. 3B. The magneticread head 300 includes a soft bias (SB) or hard bias (HB) material onboth sides of the first pinning layer 305, second pinning layer 307 andthe free layer 311 in the track width direction. The SB on both sidesare in the form of a first soft bias (or first side shield) 340 on afirst side of the layers 305, 307, 311 and a second soft bias (or secondside shield) 342 on a second side of the layers 305, 307, 311. Theinsulation material 333 is formed on both sides of the RHB 323 and thefirst pinning layer 305 in the track width direction. The magnetic readhead 300 also includes an insulation layer 373 and an insulation layer374 disposed on both sides of the layers 305, 307, 311. The insulationlayer 373 is disposed between the layers 305, 307, 311 and the firstside shield 340, and separates the layers 305, 307, 311 from the firstside shield 340. The insulation layer 374 is disposed between the layers305, 307, 311 and the second side shield 342, and separates the layers305, 307, 311 from the second side shield 342.

FIG. 3C is a schematic illustration of a front view of the magnetic readhead 300 shown in FIG. 3A, according to one implementation. The frontview is an MFS view, such as an ABS view. The first side shield 340 andthe second side shield 342 are both oriented to generate magnetic fieldsM1, M2 in the same direction along the track width direction. Each ofthe first side shield 340 and the second side shield 342 includes asingle material layer structure (as shown in FIG. 3C) disposed betweenthe upper shield S2 and the lower shield S1. Insulation layers 379, 380are formed respectively between seed layers 375, 376 and the lowershield S1. In one embodiment, which can be combined with otherembodiments, the first side shield 340 and the second side shield 342are coupled directly to the upper shield S2 and separated from the lowershield S1 through layers, such as insulation layers 373, 374, insulationlayers 379, 380, and/or seed layers 375, 376. The first side shield 340and the second side shield 342 are de-coupled from the lower shield S1using the insulation layers 373, 374, insulation layers 379, 380, and/orseed layers 375, 376. The insulation layers 379, 380 and the insulationlayers 373, 374 insulate the respective first and second side shields340, 342 from the lower shield S1. In one example, a soft bias (SB)material is used for the first and second side shields 340, 342. In oneembodiment, which can be combined with other embodiments, each of thefirst and second side shields 340, 342 includes a hard bias (HB)material, and each of the first and second side shields 340, 342 areinsulated from both the lower shield S1 (using insulation layers 373,374) and the upper shield S2 (using cap layers 377, 378, which are shownin ghost). The single material layer structure of each of the first andsecond side shields 340, 342 is formed of a single material. The singlematerial layer structure may include a single layer formed of a singlematerial, or a plurality of layers that are formed of the singlematerial and are magnetically coupled directly together. In oneembodiment, which can be combined with other embodiments, the singlematerial includes a soft bias (SB) material that is a soft magneticmaterial. In one example, the single material includes one or more ofNi, Fe, Co, or Cr, Pt, Hf, and/or an alloy thereof. The first and secondside shields 340, 342 facilitate reduced complexities relative toconfigurations, such as dual free layer reader configurations, where asynthetic anti-ferromagnetic layer (SAF) soft bias shield is alignedwith the barrier layer 315. The first and second side shields 340, 342also facilitate use of a larger RHB 323. In FIG. 3C, cross-sectionalhatching for the seed layers 375, 376, the insulation layers 379, 380,and the insulation layers 373, 374 is omitted for ease of visualreference.

In FIG. 3C, cross-sectional hatching for the cap layer 313, the barrierlayer 315, and the spacer layer 309 is omitted for ease of visualreference.

FIG. 4A is a schematic illustration of a side view of a magnetic readhead 400, according to one implementation, and may be used as themagnetic read head 211 shown in FIG. 2. The side view shown is a throatview, or an APEX view, of the magnetic read head 400. The magnetic readhead 400 is similar to the magnetic read head 300 illustrated in FIG.3A, and includes one or more of the aspects, features, components/and/orproperties thereof. The magnetic read head 400 is a read head, and maybe used as the magnetic read head 211 shown in FIG. 2. The magnetic readhead 400 includes a magnetic sensor 401 sandwiched between the lowershield S1 and the upper shield S2. The magnetic sensor 401 is similar tothe magnetic sensor 301 illustrated in FIG. 3A, and includes one or moreof the aspects, features, components/and/or properties thereof.

The magnetic sensor 401 includes a first pinning layer 405 that issimilar to the first pinning layer 305 shown in FIG. 3A, but ismagnetically oriented in a first direction D4 that points outwardly andaway from the MFS 312. A magnetization of the first pinning layer 305 isin the first direction D4. The magnetic sensor 401 includes a spacerlayer 409 that is similar to the spacer layer 309 shown in FIG. 3A, butincludes a height approximately equal to the height H1 of the firstpinning layer 405. The spacer layer 409 also includes an outward endaligned with the outward end 321 of the first pinning layer 405. Themagnetic sensor 401 includes a second pinning layer 407 that is similarto the second pinning layer 407 shown in FIG. 3A, but is magneticallyoriented in a second direction D5 that points inwardly and toward theMFS 312. A magnetization of the second pinning layer 407 is in thesecond direction D5. The second pinning layer 407 also includes a heightthat is approximately equal to the height H1 of the first pinning layer405. The second pinning layer 407 also includes an outward end 450. Theoutward end 450 is disposed inwardly of the outward end 321 of the firstpinning layer 405 (as shown in FIG. 4A) or is aligned with the outwardend 321 of the first pinning layer 405.

In FIG. 4A, cross-sectional hatching for the cap layer 313, the barrierlayer 315, and the spacer layer 409 is omitted for ease of visualreference.

The magnetic read head 400 includes a rear hard bias (RHB) 423 that issimilar to the RHB 323 shown in FIG. 3A, but is oriented to generate amagnetic field in a bias direction D6 that points in the same directionas the second direction D5 of the second pinning layer 407. The biasdirection D6 points inwardly and toward the second pinning layer 407. Alower end 444 of the RHB 423 is aligned with (as shown in FIG. 4A) orabove (as shown in ghost as 444′ in FIG. 4A) a lower end 445 of thesecond pinning layer 407. In one embodiment, which can be combined withother embodiments, the lower end 444 of the RHB 423 is exclusive of aseed layer of the RHB 423 such that the lower end 444 is a lower end ofa magnetic layer of the RHB 423. In such an embodiment, the RHB 423 mayinclude the seed layer on which the magnetic layer of the RHB 423 isformed. The lower end 444 of the RHB 423 is below an upper end 446 ofthe second pinning layer 407. An upper end 426 of the RHB 423 is abovethe upper end 446 of the second pinning layer 407. In one example, theupper end 426 of the RHB 423 is exclusive of a nonmagnetic cap layer ofthe RHB 423 such that the upper end 426 of the RHB 423 is the upper endof a magnetic layer of the RHB 423. In such an embodiment, the RHB 423may include the nonmagnetic cap layer formed on the magnetic layer ofthe RHB 423. The magnetic read head 400 includes an insulation layer 470between the second pinning layer 407 and the RHB 423 that separates theRHB 423 from the second pinning layer 407. The insulation layer 470 alsoseparates the RHB 423 from the spacer layer 409.

The layers 303, 405, 407, 409, 311, 313, and 315 are formed on the lowershield S1 using a deposition process such as physical vapor deposition(PVD) sputtering, ion beam deposition (IBD), electroplated deposition,atomic layer deposition (ALD), or chemical vapor deposition (CVD). Thelayers of the magnetic sensor 401 are milled (such as by using ionmilling) or etched to form openings for the insulation layer 470, theRHB 423, and the insulation material 433. The openings are then refilledwith the insulation layer 470, the RHB 423 and the insulation material433 using one or more deposition processes. The insulation layer 470 isdeposited prior to the RHB 423 and the insulation material 433 toelectrically isolate the RHB 423 from the second pinning layer 407 andthe spacer layer 409. The insulation material 433 includes a firstportion disposed below the RHB 423 and a second portion disposed abovethe RHB 423. The first portion of the insulation material 433 and thesecond portion of the insulation material 433 may be depositedseparately. The insulation layer 470 is in contact with the firstportion of the insulation material 433 and the second portion of theinsulation material 433. In one example, a full mill is conducted in thetrack width direction that extends fully from one side of the layers toan opposite side of the layers in the track width direction; and apartial mill is conducted in the thickness direction that stops at theupper end 446 of the second pinning layer 407.

The magnetic field in the bias direction D6 applies magnetic force tothe second pinning layer 407 and stabilizes the magnetization of thesecond pinning layer 407. Anti-parallel coupling between the first andsecond pinning layers 405 and 407 using the spacer layer 409 alsofacilitates maintaining the magnetization of the second pinning layer407 in the second direction D5 at substantially 180 degrees relative tothe magnetization in the first direction D4 of the first pinning layer405. The magnetizations of the first and second pinning layers 405, 407are also maintained substantially in the respective first and seconddirections D4, D5. The RHB 423 applies magnetic force to the secondpinning layer 407 that is larger than any magnetic force—if any—appliedto the first pinning layer 405 by the RHB 423. Large shape anisotropydue to long heights (in the stripe height direction) of the first andsecond pinning layers 405, 407 and transverse Hk induced along thestripe height direction (due to compressive stress and positivemagnetostrictive properties of the first and second pinning layers 405,407) on the first and second pinning layers 405, 407, further stabilizethe magnetizations of the first and second pinning layers 405, 407.

The present disclosure contemplates that the first direction D4, thesecond direction D5, and the bias direction D6 may be reversed such thatthe first direction D4 points inwardly, and the second direction D5 andthe bias direction D6 point outwardly.

The magnetic read head 400 includes an insulation material 433 that issimilar to the insulation material 33 shown in FIG. 3A, but is formedabove the RHB 423, below the RHB 423, and outwardly of the barrier layer315, the free layer 311, and the cap layer 313. The insulation material433 is also formed above an outward portion of the second pinning layer407, an outward portion of the spacer layer 409, and an outward portionof the first pinning layer 405. The insulation material 433 is alsoformed outwardly of the spacer layer 409, the first pinning layer 405,and the seed layer 303.

FIG. 4B is a schematic illustration of a top view of the magnetic readhead 400 shown in FIG. 4A, according to one implementation. The uppershield S2 and the cap layer 313 are omitted in FIG. 4B. The magneticread head 400 includes the soft bias (SB) on both sides of the firstpinning layer 405, the second pinning layer 407 and the free layer 311in the track width direction. The SB on both sides are in the form ofthe first side shield 340 on a first side of the layers 405, 407, 311and the second side shield 342 on a second side of the layers 405, 407,311. The insulation material 433 is formed on both sides of the RHB 423,the first pinning layer 405, and the second pinning layer 407 in thetrack width direction. The magnetic read head 400 also includes theinsulation layer 373 and the insulation layer 374 disposed on both sidesof the layers 405. The insulation layer 373 is disposed between thelayers 405, 407, 311 and the first side shield 340, and separates thelayers 405, 407, 311 from the first side shield 340. The insulationlayer 374 is disposed between the layers 405, 407, 311 and the secondside shield 342, and separates the layers 405, 407, 311 from the secondside shield 342.

FIG. 4C is a schematic illustration of a front view of the magnetic readhead 400 shown in FIG. 4A, according to one implementation. The frontview is an MFS view, such as an ABS view.

In FIG. 4C, cross-sectional hatching for the cap layer 313, the barrierlayer 315, and the spacer layer 409 is omitted for ease of visualreference.

FIG. 5A is a schematic graphical illustration of magnetic reader widthsof multiple cases of magnetic read heads with the same physical trackwidth of 25 nm, according to various implementations. The magneticreader widths are mapped as nm. FIG. 5B is a schematic graphicalillustration of skirt ratios of multiple cases of magnetic read heads,according to various implementations. For the graph shown in FIG. 5B,skirt ratio is defined as a ratio of magnetic width at 10% amplitude tothat of 50% amplitude from microtrack profile. FIG. 5C is a schematicgraphical illustration of linear resolutions of multiple cases ofmagnetic read heads, according to various implementations. The linearresolutions are mapped as percentages.

Case 1 represents using a conventional magnetic sensor with an AFM layerincluded in a film stack with a read gap of 25 nm. Case 2 representsusing a magnetic sensor with two free layers (which may be referred toas a dual free layer, or DFL, configuration) with a read gap of 20 nm.Case 3 represents using a magnetic sensor with an AFM layer recessedfrom an MFS with a read gap seen from the MFS side of 20 nm.

Case 4 represents using the magnetic read head 400 shown in theimplementations of FIGS. 4A-4C. Case 5 represents using the magneticread head 300 shown in the implementations of FIGS. 3A-3C, where theheight H1 of the first pinning layer 305 is about 30 nm. Case 6represents using the magnetic read head 300 shown in the implementationsof FIGS. 3A-3C, where the height H1 of the first pinning layer 305 isabout 90 nm. In all cases, heights in the stripe height direction of thefree layer and pinning layers are 30 nm unless specified otherwise.

As shown in FIGS. 5A-5C, Cases 4-6 using aspects disclosed hereininvolve benefits such as reduced magnetic reader widths, reduced skirtratios, and/or increased linear resolutions relative to Cases 1-3. InFIG. 5A, Case 5 has a lesser magnetic reader width than Cases 1-3, andCases 4 and 6 have lesser magnetic reader widths than Cases 1 and 2. InFIG. 5B, Cases 4-6 have lesser skirt ratios than Cases 1 and 3. In FIG.5C, Cases 4-6 have greater linear resolutions than Cases 1-3. Hence,aspects disclosed herein can facilitate increased resolution and reducedskirt ratio while maintaining or reducing magnetic reader width withthinner reader gaps, without specialized stitching processes or separatedeposition for AFM layers in Case 3. Such aspects facilitate increasedareal density capability (ADC). In Cases 4-6, a read gap of 20 nm isused.

Benefits of the present disclosure include reduced magnetic readerwidths, smaller skirt ratios in the track width direction whileincreasing resolutions, simpler deposition and formation processes,eliminated use of specialized stitching and separate deposition of AFMlayers, using single free layers with no AFM layers, reduced readergaps, reduced skirt ratios, increased ADC, stabilized pinning layers,reduced complexities relative to configurations where SAF side shieldsare in need of alignment with barrier layers, independent control of RHBand side shields, and increased cross track squeeze capability.

It is contemplated that one or more aspects disclosed herein may becombined. As an example, aspects of the magnetic sensor 401 may becombined with aspects of the magnetic sensor 301. Moreover, it iscontemplated that one or more aspects disclosed herein may include someor all of the aforementioned benefits.

In one embodiment, a magnetic read sensor comprises a media facingsurface and a first pinning layer magnetically oriented in a firstdirection. The first pinning layer includes an inward end at the mediafacing surface and an outward end. A second pinning layer is formedabove the first pinning layer and magnetically oriented in a seconddirection that is opposite of the first direction. The second pinninglayer includes an inward end at the media facing surface and an outwardend. A spacer layer is between the first pinning layer and the secondpinning layer. A free layer is formed above the second pinning layer,and the free layer includes an inward end disposed at the media facingsurface and an outward end. A barrier layer is between the secondpinning layer and the free layer. A rear hard bias is disposed outwardlyof the first pinning layer relative to the media facing surface. Therear hard bias is magnetically oriented to generate a magnetic field ina bias direction that points in the same direction as the firstdirection of the first pinning layer. The rear hard bias includes a seedlayer, a magnetic layer on the seed layer, and a nonmagnetic cap layeron the magnetic layer. An upper end of the rear hard bias is alignedwith or above an upper end of the first pinning layer. The upper end ofthe rear hard bias is below an upper end of the second pinning layer.The outward end of the second pinning layer and the outward end of thefree layer are disposed inwardly of the outward end of the first pinninglayer, and the magnetic read sensor includes an insulation materialformed above the rear hard bias and outwardly of the free layer and thesecond pinning layer. The magnetic read sensor also includes aninsulation layer formed between the rear hard bias and the first pinninglayer. A magnetic layer of the rear hard bias is formed of a materialincluding one or more of Co, Pt, or Cr. The magnetic read sensor alsoincludes a lower shield below the first pinning layer, an upper shieldabove the free layer, and a cap layer between the free layer and theupper shield. The spacer layer includes Ru and the barrier layerincludes MgO or Al2O3. A magnetic recording device including themagnetic read sensor is also disclosed.

In one embodiment, a magnetic read sensor comprises a media facingsurface, and a first pinning layer magnetically oriented a firstdirection. The first pinning layer includes an inward end at the mediafacing surface and an outward end. A second pinning layer is formedabove the first pinning layer and magnetically oriented in a seconddirection that is opposite of the first direction. The second pinninglayer includes an inward end at the media facing surface and an outwardend. A spacer layer is between the first pinning layer and the secondpinning layer. A free layer formed above the second pinning layer, andthe free layer includes an inward end disposed at the media facingsurface and an outward end. A barrier layer is between the secondpinning layer and the free layer. A rear hard bias is disposed outwardlyof the second pinning layer relative to the media facing surface, andthe rear hard bias is magnetically oriented to generate a magnetic fieldin a bias direction. The bias direction points in the same direction asthe second direction of the second pinning layer. A lower end of therear hard bias is aligned with or above a lower end of the secondpinning layer. The upper end of the rear hard bias is above an upper endof the second pinning layer. The outward end of the free layer isdisposed inwardly of the outward end of the second pinning layer andinwardly of the outward end of the first pinning layer. The magneticread sensor also includes an insulation material formed above the rearhard bias, below the rear hard bias, and outwardly of the free layer,and an insulation layer formed between the rear hard bias and the secondpinning layer. The insulation material is formed above a portion of thesecond pinning layer and above a portion of the first pinning layer. Amagnetic layer of the rear hard bias is formed of a material includingone or more of Co, Pt, or Cr. A magnetic recording device including themagnetic read sensor is also disclosed.

In one embodiment, a magnetic read sensor comprises a media facingsurface, a lower shield, and a first pinning layer formed above thelower shield and magnetically oriented in a first direction. The firstpinning layer includes an inward end at the media facing surface and anoutward end. The magnetic read sensor also includes a second pinninglayer formed above the first pinning layer and magnetically oriented n asecond direction that is opposite of the first direction. The secondpinning layer includes an inward end at the media facing surface and anoutward end. The magnetic read sensor also includes a free layer formedabove the second pinning layer, and the free layer includes an inwardend disposed at the media facing surface and an outward end. Themagnetic read sensor also includes an upper shield formed above the freelayer, and a first side shield formed on a first side of the firstpinning layer, the second pinning layer, and the free layer. The firstside shield includes a single material layer structure coupled to theupper shield and separated from the lower shield through an insulationlayer. The magnetic read sensor also includes a second side shieldformed on a second side of the first pinning layer, the second pinninglayer, and the free layer. The second side shield includes a singlematerial layer structure coupled to the upper shield and separated fromthe lower shield through an insulation layer. The outward end of thefirst pinning layer is disposed outwardly of the outward end of thesecond pinning layer and outwardly of the outward end of the free layer.A magnetic recording device including the magnetic read sensor is alsodisclosed.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A magnetic read sensor, comprising: a first pinning layer magnetically oriented in a first direction, the first pinning layer comprising an inward end at a media facing surface and an outward end; a second pinning layer formed above the first pinning layer and magnetically oriented in a second direction that is opposite of the first direction, the second pinning layer comprising an inward end at the media facing surface and an outward end; a spacer layer between the first pinning layer and the second pinning layer; a free layer formed above the second pinning layer, the free layer comprising an inward end disposed at the media facing surface and an outward end, wherein the outward end of the free layer is disposed inwardly of the outward end of the second pinning layer and inwardly of the outward end of the first pinning layer; a barrier layer between the second pinning layer and the free layer; and a rear hard bias disposed outwardly of the second pinning layer relative to the media facing surface, the rear hard bias magnetically oriented to generate a magnetic field in a bias direction that points in the same direction as the second direction of the second pinning layer; an insulation material formed above the rear hard bias, below the rear hard bias, and outwardly of the free layer, wherein the insulation material is formed above a portion of the second pinning layer and above a portion of the first pinning layer; and an insulation layer formed between the rear hard bias and the second pinning layer.
 2. The magnetic read sensor of claim 1, wherein a lower end of the rear hard bias is aligned with or above a lower end of the second pinning layer.
 3. The magnetic read sensor of claim 2, wherein an upper end of the rear hard bias is above an upper end of the second pinning layer.
 4. The magnetic read sensor of claim 1, wherein a magnetic layer of the rear hard bias is formed of a material including one or more of Co, Pt, or Cr.
 5. A magnetic recording device comprising the magnetic read sensor of claim
 1. 6. The magnetic read sensor of claim 1, wherein a lower end of the rear hard bias is above a lower end of the second pinning layer, and an upper end of the rear hard bias is above an upper end of the second pinning layer.
 7. The magnetic read sensor of claim 1, wherein the spacer layer is in contact with each of the first pinning layer and the second pinning layer, and the spacer layer is nonmagnetic and formed of a metal material that is Ru.
 8. The magnetic read sensor of claim 7, wherein the spacer layer is of a thickness that is within a range of 4 Å to 9 Å.
 9. A magnetic read sensor, comprising: a first pinning layer magnetically oriented in a first direction, the first pinning layer extending a first distance from a media facing surface; a second pinning layer formed above the first pinning layer and magnetically oriented in a second direction that is opposite of the first direction, the second pinning layer extending a second distance from the media facing surface that is less than the first distance; a spacer layer between the first pinning layer and the second pinning layer; a free layer formed above the second pinning layer, the free layer comprising an inward end disposed at the media facing surface and an outward end; a barrier layer between the second pinning layer and the free layer; and a rear hard bias disposed outwardly of the second pinning layer relative to the media facing surface, the rear hard bias magnetically oriented to generate a magnetic field in a bias direction that points in the same direction as the second direction of the second pinning layer.
 10. The magnetic read sensor of claim 9, wherein the spacer layer extends a third distance from the media facing surface, wherein the third distance is less than the first distance.
 11. The magnetic read sensor of claim 10, wherein the third distance is equal to the second distance.
 12. The magnetic read sensor of claim 10, wherein the second pinning layer has a lower end that is aligned with a lower end of the rear hard bias.
 13. The magnetic read sensor of claim 10, wherein a lower end of the rear hard bias is above a lower end of the second pinning layer.
 14. The magnetic read sensor of claim 13, wherein an upper end of the rear hard bias is above an upper end of the second pinning layer.
 15. A magnetic recording device comprising the magnetic read sensor of claim
 10. 16. A magnetic read sensor, comprising: a first pinning layer magnetically oriented in a first direction; a second pinning layer formed above the first pinning layer and magnetically oriented in a second direction that is opposite of the first direction, wherein the first pinning layer has a larger stripe height than the second pinning layer; a spacer layer between the first pinning layer and the second pinning layer; a free layer formed above the second pinning layer, the free layer comprising an inward end disposed at a media facing surface and an outward end; a barrier layer between the second pinning layer and the free layer; a rear hard bias disposed outwardly of the second pinning layer relative to the media facing surface, the rear hard bias magnetically oriented to generate a magnetic field in a bias direction that points in the same direction as the second direction of the second pinning layer; and an insulation layer disposed between the spacer layer and the rear hard bias.
 17. The magnetic read sensor of claim 16, wherein a lower end of the rear hard bias is above a lower end of the first pinning layer.
 18. The magnetic read sensor of claim 17, wherein the lower end of the rear hard bias is above an upper end of the first pinning layer.
 19. A magnetic recording device comprising the magnetic read sensor of claim
 16. 20. The magnetic read sensor of claim 16, wherein a lower end of the rear hard bias is above a lower end of the second pinning layer, and an upper end of the rear hard bias is above an upper end of the second pinning layer. 